Processing facilities are typically managed using process control systems. Among other functions, these control systems often manage the use of valves in the processing facilities. The valves typically control the flow of materials in the facilities. Example processing facilities include manufacturing plants, chemical plants, crude oil refineries, and ore processing plants. In these facilities, the valves may control the flow of water, oil, hydrochloric acid, or any other or additional materials in the facilities.
The valves used in the processing facilities often suffer from a number of problems or defects. For example, a valve may suffer from valve hysteresis or valve stiction. Valve hysteresis occurs when the valve is moving in one direction, the control system instructs the valve to move in the opposite direction by a specified amount, and the valve moves in the opposite direction by less than the specified amount. Valve stiction, which is short for static friction, refers to the resistance to the start of motion. It occurs when the valve fails to respond to pressure meant to adjust the opening of the valve. The valve fails to respond until additional pressure is added, which causes the valve to open or close more than desired. These or other defects often limit or prevent the control systems from accurately controlling the flow of materials using the valve.